Study of the Benefits of Roundabouts

Since local planners seem to have fallen in love with the roundabout, I thought I would link to this 2009 Transport Canada report. From the introduction:

“The use of roundabouts instead of intersections has gained much attention and momentum over the last 10 years in North America. Approximately 50% of personal injury crashes and 30% of fatalities occur at intersections or are related to intersections (Ontario Ministry of Transportation, 2003). At locations where it is possible to implement roundabouts, this risk can be significantly reduced. In the traffic safety community the considerable benefits in reduction of injuries and improvement in mobility, with positive economic and social benefits, are increasingly recognized. The U.S. Federal Highway Administration (FHWA) has recently developed guidelines for their implementation and is promoting their application. In Canada the Transportation Association of Canada (TAC) is in the process of developing guidelines.

“Roundabouts have environmental, economic, and social benefits in addition to those of safety. This report addresses the various impacts of roundabouts through literature review and brief telephone interviews with transportation personnel in Canadian and U.S. jurisdictions. ”

It isn’t all good, though, for those most negatively affected:

“2.2 Road User Challenges

“From a safety, mobility and emissions perspective roundabouts are highly beneficial for light vehicle motorists. However, their continuous flow can present challenges for pedestrians, especially blind pedestrians and bicyclists. Pedestrians can be accommodated easily at single-lane roundabouts, where safety is improved because of the splitter island that allows pedestrians to deal with crossing one direction of traffic at a time. However multi-lane facilities require careful placement of crosswalks and design of signals. Signals should use offset phases to avoid traffic backing up into the circulatory roadway.

“Based on cyclist crash statistics, roundabouts are safer than stop and yield-controlled intersections, but multi-lane roundabouts are worse than signalized intersections. Studies show that in multi-lane roundabouts, cyclists benefit from narrow entry points, allowing light vehicles to enter side by side, but forcing trucks to straddle two lanes.”

One Response

Keep in mind that this is about roundabouts and NOT the circles that are built around here. The Capital Region circles or often badly designed, some even have turn only lanes in them. Circles = Boooo! Roundabouts = Yay!
As for pedestrians crossing large roundabouts, I wonder if it is worthwhile to add tunnels or bridges for those cases. They do not need to be as high and wide as a tunnel for a car. While that would be the safest way, tunnels may come with other problems, such as requiring lighting. Bridges would need to be high enough to allow trucks to pass under. And in both cases stairs would make them unusable for handicapped people.